[1] : The Collaborative International Dictionary of English v.0.48

gardening \gar"dening\, n.
   the art of occupation of laying out and cultivating gardens;
   horticulture.
   1913 webster

[2] : The Collaborative International Dictionary of English v.0.48

garden \gar"den\, v. i. imp.  p. p. gardened; p. pr.  vb.
   n. gardening.
   to lay out or cultivate a garden; to labor in a garden; to
   practice horticulture.
   1913 webster
see also:
gardened gardening 

[3] : WordNet (r) 2.0

gardening
     n : the cultivation of plants syn: horticulture
see also:
horticulture 

[4] : Moby Thesaurus II by Grady Ward, 1.0

25 moby thesaurus words for "gardening":
   bloom, blossom, blow, citriculture, floret, floriculture, floscule,
   flower, flower gardening, flower-growing, floweret, fruit-growing,
   groundskeeping, horticulture, hortorium, landscape architecture,
   landscape gardening, market gardening, olericulture, orcharding,
   pomiculture, posy, truck gardening, viniculture, wildflower

Gardening >> G Words
Gardening, definition of term: Gardening
gardening_pag1.html